In a sweeping set of announcements, the final $35 million payment on the $100 million Largs Bay amphibious craft purchased from the UK, the signing of a $133 million contract to buy 101 Bushmaster vehicles and the roll out of additional C-RAM early warning rocket systems to Australian forward operating bases in Afghanistan were all also announced.

The new Seahawk helicopters, which will be purchased off the shelf, were selected ahead of the NATO Helicopter Industries NH90 NFH which would have been built by Australian Aerospace.

Mr Smith said the Seahawk's proven capability with the US Navy had been decisive factor, as well as its interoperability with the US Navy.

"The Romeo is a proven capability currently operated by the United States Navy. The United States Navy has accepted around 100 Romeos which have accumulated 90,000 flying hours, including on operational deployments," Mr Smith said.

"Because of its proven capability it's low risk and also we very strongly believe it is value for money," he said.

Mr Clare said the helicopters would be based at HMAS Albatross in Nowra and would operate from the back of ANZAC frigates as well as the new air warfare destroyers.

"Their job is to hunt and kill submarines they also will play an important role in attacking small and fast moving water craft," he said.

"And like the our Seahawk helicopters that operate off our frigates now in the middle east and the coast of Africa they will playa very important role when it comes to anti piracy and counter-terrorist activities."

"This is a big and important decision. It's worth more than $3 billion and worth even more than that to Australia security."

On the review of civilian access to the Garden Island naval base, Mr Smith said he had appointed Mr Hawke to conduct the review following his successful review of the future use of the Woomera protected area.

"Our on-going primary obligation and capacity has to be of course for navy and military arrangements," he said.

But Mr Smith struck a note of caution on the prospect of cruise ships gaining access to the naval facility with the arrival of the Largs Bay, two landing helicopter docks that are larger than Australia largest aircraft carrier and two air warfare destroyers.

"There are considerable constraints on Garden Island but I want that independent review to be conducted," he said.

The deal with Sikorsky Lockheed Martin comes three years after then-Defence Minister Joel Fitzgibbon dropped Australia's $1 billion commitment to the Seasprite project and 15 months after the tender process began.

The Seahawk helicopters will begin entering service with the Navy from mid-2014 and the roll out will finish in 2020.

A review into the civilian access to air force airfields was also announced, with the civil aviation industry invited to comment on that review by the October 31.

"We want to see if it's possible to provide greater access to about a dozen or so of our airfields," Mr Smith said.

"Again, the starting point has to be that our air force airfields are of course for air force and defence purposes but we are waiting to see if greater sensible access to airfields is appropriate."